Air Rights usage in a landmarked historic district

Assume extra floors will be set back to comply with the light requirements / sliver law. Who is the right professional to consult? Landmark Law firm, Architect or Expeditor? Thank you.

Architect I believe. I have seen these air rights calculations and they are pretty complicated, requiring exact measurements of exterior dimensions including lot coverage, yard calculations and overhangs. Something as simple as a slight encroachment can cancel any benefits.

So, in order to maximize air rights, you might need to tear down some of the building such as architectural overhangs, encroachments or single story additions. At least this is the study I read years ago for a church transferring air rights to a vacant site. May be different in your case.

Fortunately, what I am exploring is simpler as it is purely a matter of being able to add additional floors to an elevator townhouse to utilize air rights. I may have to talk to a landmark specialist firm it seems.

This is something better reserved for a conversation with a licensed architect vs on a forum, just imo :-)